A computer device and method for encoding a message corresponding to an outcome of a computer game, and a computer device and method for decoding the message to detect a fraudulent outcome. The computer device used to generate the encoded message includes (1) a memory device containing encoding control code and (2) a processor configured to process the encoding control code in conjunction with a computer game outcome to generate an encoded message containing the computer game outcome and to transmit the encoded message to a human-readable output device, such as a display device. The computer device includes various tamper resistant or tamper evidence features. A secure module containing the processor and memory is used to plug into an existing personal computer or dedicated game device. The method for encoding the message includes the steps of executing a computer game program to generate a computer game outcome, encoding the computer game outcome to generate an encoded message, and providing the encoded message to a user, who may then transmit the encoded message to a device configured for decoding the encoded message to reveal the computer game outcome. A second central or host computer device is used to decode the encoded message. The second computer device has (a) a memory device containing decoding control code and an encoded message corresponding to a computer game outcome and (b) a processor configured to process the code to decode the encoded message to reveal the computer game outcome.